Being a good American, I just increased my defense budget again... Here is my brand new electric fence addition. About $80 total from Tractor Supply, actually not that expensive, and I even went with the stronger "5 mile" controller, mainly because it has better mounting options and a separate power cable instead of plugging right into an outlet. I put it on a timer so it's only active at night after the door to the coop is closed. I don't want any of the girls to get zapped if they fly over or onto the 5' fence, which they do on occasion.